1. Field of Invention
The invention is related to the field of electric screw actuator systems which are to be applied as the main drive for all kinds of tasks, such as the electric drive and control of the steering device of a vehicle, the brake device thereof etc.
2. Description of Related Art
A major point of concern in the field of electric screw actuator systems is the degree of reliability of the electric components thereof, including the supply of electric current which is necessary for powering the system.
Although the reliability has meanwhile been raised to a level which is accepted in most fields of technology, e.g. the aircraft industry, and the automotive industry, nevertheless several reasons still exist to apply a mechanical back-up system. Such mechanical back-up system might not always be necessary for reasons of lack of reliability, but other reasons, such as a feeling of confidence by the car driver, (long term) garage parking etc. may make it desirable to incorporate a mechanical back-up.